1. Field of Invention
The present invention relates to an automotive impact energy absorbing structure and, more particularly, to an impact energy absorbing structure for absorbing impact energy applied to an upper portion of a body of a motor vehicle from inside a compartment, using an energy absorbing member that deforms to absorb the impact energy applied thereto.
2. Description of Related Art
Japanese patent application laid-open Nos. Hei 8-119047 and Hei 8-127298 propose automotive energy absorbing structures for absorbing impact energy using a resin-made energy absorbing body (for example, a grating-like rib) that is disposed in a space between a pillar having an inner panel and a pillar garnish disposed at a passenger compartment interior side and separated from the inner panel by the space.
If the energy absorbing body is formed as a resin-made grating-like rib member, the amount of energy absorbed by the member during an initial period of application of impact energy is relatively small since plastic deformation of the resin-made grating-like rib member starts late relative to the amount of deformation. Furthermore, the resin-made grating-like rib member is subject to changes in load bearing strength due to temperature or humidity changes and, in some environments, tends to deteriorate over time, thus resulting in a decreased capacity for energy absorption. Therefore, in designing energy absorbing resin-made grating-like rib members, the dimensions thereof are determined so that the members remain able to absorb desired amounts of energy even when they deteriorate. Thus, the energy-absorbing members inevitably become large in size.